It's been one week since police recovered the bodies of two sisters from the Hudson River in New York City, and they are still trying to determine how the women got into the water.

Authorities say that Rotana Farea, 22, and Tala Farea, 16, were both dressed in similar black leggings and fur-trimmed jackets, and bound together at their waists and ankles by duct tape. In a press conference Wednesday, New York police said the medical examiner determined the sisters were both alive when they entered the water, but the exact cause of death is not known and there are no obvious signs of trauma. NYPD Chief of Detectives Dermot Shea said this "has not been determined a homicide," but the deaths are considered suspicious. The sisters did not have registered phones or social media profiles.

The sisters were citizens of Saudi Arabia. A law enforcement source told CBS News that their mother, who lives in Virginia, told police that earlier this month, the Saudi government called her and said the family had to return to the kingdom because the sisters had applied for asylum in the United States. The Saudi consulate in New York on Tuesday said the sisters were students who accompanied their brother to Washington; CBS News reports they lived in Fairfax, Virginia, and were last seen there in September. Catherine Garcia

He's been fielding phone calls from people who want to know why he's leaving, but House chaplain Rev. Patrick J. Conroy says he has no idea why House Speaker Paul Ryan (R-Wis.) asked him to resign earlier this month.

In an interview with The New York Times, Conroy said the message came from Ryan's chief of staff, and he was blindsided by the request. He notified Ryan in an April 15 letter that he was stepping down, at Ryan's request, on May 24. "I certainly wasn't given anything in writing," Conroy said. "Catholic members on both sides are furious." The nonpartisan House chaplain gives a prayer each day the House is in session, and Conroy has held the position since 2011.

Republicans and Democrats are preparing a letter asking Ryan for an explanation. Conroy told the Times that Ryan may have been motivated by his Nov. 6 opening prayer, as the GOP tax bill was being discussed: "May all members be mindful that the institutions and structures of our great nation guarantee the opportunities that have allowed some to achieve great success, while others continue to struggle. May their efforts these days guarantee that there are not winners and losers under new tax laws, but benefits balanced and shared by all Americans."

Conroy said a week later, a Ryan aide told him they were "upset" by the prayer and he was getting "too political," and Ryan later told him, "Padre, you've got to stay out of politics." Conroy doesn't see the problem. "If you are hospital chaplain, you are going to pray about health," he said. "If you are a chaplain of Congress, you are going to pray about what Congress is doing." Rep. Walter Jones (R-N.C.) told the Times he's "very upset" by Conroy's resignation, and "if this is true about the prayer, and we have freedom of religion in America, how about freedom of religion on the floor of the House? The members of the House vote for the chaplain. This is not a one-man decision." Catherine Garcia

State security agents are trying to track down the mysterious author of a short letter published online, calling for the resignation of Chinese President Xi Jinping.

Since the letter first appeared on Canyu, a U.S.-based Chinese language website edited by a human rights activist named Cai Chu, more than two dozen people believed to have some connection to the letter have been detained, The Guardian reports. The letter, addressed to "Comrade Xi Jinping" and signed "loyal Communist party members," says the authors feel Xi does not "possess the capabilities to lead the party and the nation into the future, and we believe that you are no longer suitable for the post of general secretary."

After the letter appeared on Canyu, it showed up on the Chinese news site Wujie; censors took it down that day, the site was shut down, and authorities detained several staff members, The Guardian reports. Several exiled journalists also say their relatives have been detained in China and questioned about any ties they may have to the letter. As Chinese officials continue their search for the writer, and experts discuss whether or not this is all a prank or actual Communist Party dissent, William Nee of Amnesty International in Hong Kong says Xi's plan is "backfiring. Conducting an aggressive manhunt against anyone allegedly involved in commenting on the letter only serves to put more attention on the letter, giving it a longer shelf life." Catherine Garcia

Since May, 30 dead whales — 11 fin whales, 14 humpbacks, one gray whale, and four unidentified cetaceans — have been discovered, and the National Oceanic and Atmospheric Administration declared an "unusual mortality event" on Thursday, The Huffington Post reports. Last year, just five dead whales were spotted on the coast. "While we do not yet know the cause of these strandings, our investigations will give us important information on the health of whales and the ecosystems where they live," NOAA's Dr. Teri Rowles said in a statement.

Because the coastline of Alaska is so vast, scientists have only been able to get to one of the whale carcasses. It's possible the deaths are being caused by toxic algae bloom, NOAA said, but it's "highly unlikely" the strandings are due to radiation from Fukushima. The scientists say it could take years to figure out what's going on, and are asking the public to call them if they see a dead whale or a living whale in distress. Catherine Garcia

On Monday, the Waller County, Texas, Sheriff's Office released three hours of video footage from a camera aimed at the hallway outside the jail cell of Sandra Bland, a 28-year-old black woman found dead in her cell on July 13. Bland, 28, had been stopped by a sheriff's deputy on July 10 for changing lanes without a signal, and then arrested after, the deputy said, Bland assaulted him. The sheriff's office said it will release dash-cam video of the arrest on Tuesday.

Monday's video shows a sheriff's deputy discovering Bland's body and running to get help, but it shows no movement for about 90 minutes before that — sheriff's department officials said that on the morning of her death, Bland refused a food tray about 6:30 a.m. and was found dead with a garbage bag around her neck just after 9 a.m. The county coroner ruled the death a suicide, but Bland's family finds that unlikely, arguing that Bland just moved to Houston to take a new job she was excited about. The Waller County district attorney, Elton Mathis, promised a full, thorough investigation.

"It is very much too early to make any kind of determination that this was a suicide or a murder because the investigations are not complete," Mathis said, adding: "This investigation is still being treated just as it would be in a murder investigation. There are many questions being raised in Waller County, across the country and the world about this case. It needs a thorough review." The FBI and Texas Rangers are helping with the case, and Mathis said he will impanel a grand jury in August. Capt. Brian Cantrell at the sheriff's department said that Bland's death "was a tragic incident, not one of criminal intent or a criminal act" but that he welcomed the investigation. You can watch part of the video below.Peter Weber

Kathleen Danise, 60, was at Salty Brine State Beach in Narragansett when suddenly, she was launched into nearby rocks, ABC News reports. "She was like a human cannon," her sister, Laura Demartino, told WTNH. Officials say they are taking the matter seriously, and are concerned that they don't know what caused the explosion.

Janet Colt, director of the Rhode Island department of environmental management, said they're looking at cables below the sand that were "de-energized" in 2007, and officials aren't ruling out the possibility of an energized cable. Several beach goers said they smelled gas after the explosion, but a spokesman for National Grid said there are no gas lines along the beach. Rhode Island fire marshal Jack Chartier said there was no evidence of any explosives, but investigators are "leaving no stone unturned." Catherine Garcia

Two of those women are still missing, while four have been found dead. Officials say they are connected through a common history of drug use, possible prostitution, and mutual friends, The Chillicothe Gazette reports. One of the women was found with three gunshots to the head, and another died from an "undetermined circumstance." The coroner ruled that one woman, whose car was found abandoned with a drained battery and the doors open, committed suicide by drowning, but her family said she was not despondent and was excited to be pregnant.

The community is holding marches and vigils, and raising money to pay for the burial of one of the women. The FBI has been called in to help crack the cases, but despite the fact there is a dedicated tip line, not enough clues are coming in to aid police. "We've checked land, air, and water for any signs of the [the women]," Chillicothe Police Chief Keith Washburn said. "But the problem is you're trying to find a needle in a haystack unless you have the information. The information we have is running dry on some of these cases." Catherine Garcia

White House Press Secretary Josh Earnest was unable to say early Monday what the unidentified "device" was that the Secret Service found somewhere on the White House grounds, nor where it was found, but he did say that "early indications are that it does not pose any sort of ongoing threat right now to anybody at the White House." The New York Timessuggests that maybe the object was a drone.

Earnest spoke from New Delhi, India, where he's traveling with President Obama and the first lady, and he referred all further questions to the Secret Service. Obama daughters Sasha and Malia stayed behind in Washington. You can watch Earnest not provide much information below. —Peter Weber